Dye-surfactant interaction: Role of an alkyl chain in the localization of styrylpyridinium dyes in a hydrophobic force field of a cationic surfactant (CTAB)

Article abstract of DOI:10.1246/bcsj.70.2913

The interaction of a number of cationic dyes (I) with a varying number of methylene groups (C(n)) in the alkyl chain attached to pyridyl nitrogen with a cationic surfactant (CTAB) assembly is reported. The binding constant of the dyes (Cs to C₁₈) with the micelle have been calculated, and are found to increase with increasing carbon chain. A plot of the binding constant vs. the chain length shows a curve with a maximum for C₁₆, which is attributed to a compatibility factor. From studies of the electronic and emission spectra it is proposed that a micelle has a hydrophobic force field and that the dyes are localized in various pockets of the field.